(80c) Metal Oxide Based Solar Driven Two-Step Methane Reforming and Water Splitting Cycle

H₂ production via metal oxide based solar thermochemical splitting of H₂O is considered as one of the alternatives for the gasification and reforming of fossil fuels, pyrolysis and reforming of biomass, ethanol decomposition, and others. Various metal oxide based thermochemical cycles such as zinc oxide cycle, tin oxide cycle, iron oxide cycle, ferrite cycle, ceria cycle, perovskite cycle, and others have been investigated towards the solar production of H₂ via water splitting reaction. The major limitation associated with this process is the requirement of a very high temperature for the reduction of the metal oxide. This issue can be addressed if the metal oxide based H₂O splitting process is coupled with the CH₄ reforming process.

Recently, metal oxide (MO) based two-step CH₄ reforming and H₂O/CO₂ splitting cycle receiving much attention for co-production of syngas and H₂. As explained above, in first step, the MO is reduced using CH₄ as the reducing agent producing synags (combined H₂ and CO). The reduced MO can be re-oxidized using H₂O, CO₂, or combined stream of H₂O/CO₂ for the production of H₂, CO, or syngas. In this study, the equilibrium thermodynamic analysis is performed to study the effect of CH₄/metal oxide ratio on equilibrium compositions and the temperatures required to achieve higher levels of fuel production. Likewise, the solar reactor efficiency analysis is conducted to determine the solar-to-fuel energy conversion efficiency of this cycle. The investigated metal oxide is further synthesized and characterized using various analytical techniques. The synthesized metal oxide is tested towards CH₄ reforming and H₂O/CO₂ splitting reaction using a thermogravimetric analyzer (coupled with GC-MS). Effects of CH₄ concentration, reforming and splitting temperatures on the fuel production is also explored. The obtained results are compared with previous thermochemical cycles and will be presented in detail.